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Published on: October 5, 2012
Expression of Bcl-x in normal skin and benign cutaneous adnexal tumors
Thomas P Thamboo1, Leonard H-C Tan, Soo-Yong Tan
1Department of Pathology, National University of Singapore, Singapore. pattpt@nus.edu.sg
Background:
Bcl-x appears to have an antiapoptotic role in the epidermis. Little is known about the expression of Bcl-x in cutaneous adnexal structures and benign cutaneous adnexal tumors.
Methods:
Tissues from 31 cases of benign cutaneous adnexal tumors (five trichofolliculomas, five trichoepitheliomas, two sebaceous adenomas, five apocrine hidradenomas, five eccrine poromas, five eccrine spiradenomas, and four syringomas) were immunostained for Bcl-x.
Results:
Strong staining for Bcl-x was seen in cells of the epidermal granular layer and inner root sheath of hair follicles. Sebaceous gland cells showed strong staining. Apocrine gland cells showed weak to moderate staining. No staining was seen in eccrine gland cells. The basaloid cells of trichofolliculomas and trichoepitheliomas showed no staining. In sebaceous adenomas, the sebaceous cells showed strong staining while the basaloid cells were negative. The cells of apocrine hidradenomas showed patchy weak staining. No staining was seen in eccrine poromas, eccrine spiradenomas, and syringomas.
Conclusions:
The degree of Bcl-x expression in cutaneous adnexal glandular structures appears to be related to their mode of secretion, being strongest in cells with apoptotic degradation of the entire cell (sebocytes). This pattern is recapitulated in the corresponding benign cutaneous adnexal tumors. Bcl-x may be useful in identifying cells with sebaceous differentiation in poorly differentiated adnexal tumors.
Insights
Bcl-x, an antiapoptotic protein, is expressed in sebaceous and apocrine glands but not eccrine glands. This pattern is mirrored in benign adnexal tumors, aiding in identifying sebaceous differentiation.
Area of Science:
- Dermatopathology
- Molecular biology
- Oncology
Background:
- Bcl-x (B-cell lymphoma extra large) is an antiapoptotic protein.
- Its role in the epidermis is established, but expression in cutaneous adnexal structures and tumors is largely unknown.
Purpose of the Study:
- To investigate the expression of Bcl-x in various benign cutaneous adnexal tumors.
- To correlate Bcl-x expression with the secretory function of adnexal glands.
Main Methods:
- Immunohistochemical staining for Bcl-x was performed on 31 benign cutaneous adnexal tumors.
- Tumor types included trichofolliculomas, trichoepitheliomas, sebaceous adenomas, apocrine hidradenomas, eccrine poromas, eccrine spiradenomas, and syringomas.
Main Results:
- Strong Bcl-x staining was observed in epidermal granular cells, hair follicle inner root sheath, and sebaceous gland cells.
- Apocrine gland cells showed weak to moderate staining, while eccrine gland cells had no staining.
- Benign tumors recapitulated these patterns, with sebaceous adenomas showing strong staining in sebocytes and no staining in basaloid cells.
Conclusions:
- Bcl-x expression in adnexal glands correlates with their mode of secretion, notably high in sebocytes.
- This expression pattern is consistent in corresponding benign tumors.
- Bcl-x may serve as a marker for sebaceous differentiation in challenging adnexal tumor diagnoses.
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